Master clip arrangements for hectographic duplicating machines



Apnl 7, 1959 E. BROUGHAM ETAL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES FiledSept. 20. 1955 5 Sheets-Sheet 1 8 m a m Alum rats .Filed Sept. 20; 1955April 1959 L. E. BROUGHAM ET AL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC 1 DUPLICATING MACHINES 5Sheets-Sheet 2 F'LGb-Q FIG].

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MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES 5Sheets-Sheet 4 Filed Sept.. 20, 1955 m M m a we @QE 5% 8 mo\ mmw P 3 m9k mm 5 mm a a Pa... 3 3 u M g inwl much N FFEHPILL F nn!- Lvj..- NW

April 7,- 1959 L. E. BROUGHAM ET'AL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES 5Sheets-Sheet 5 Filed Sept. 20, 1955 Z; M? w 2% 59A/ /W/ MASTER CLII."ARRANGEMENTS FOR HECTO GRAPHIC DUPLICATING MACHINES Leslie ErnestBrougham, and Roland Brown, London, England, assiguors to Block &Anderson Limited, London, England, a British company ApplicationSeptember 20,1955, SerialNo. 535,436,

Claims priority, application Great Britain September22, 1954 13. Claims.(Cl. 101-4325.)

The present invention relates to. master clip arrangements inhectographic duplicatingv machines and more particularly to adjustingmechanisms. for the master clips of such machines.

' In machines of the to whichthe invention re: lates, one or morehectographic master sheets carrying typewritten or other matter inmirror scripare, each secured, by means of a. device known as a clip, toa rotatable printing drum. co-operating with a counter pres-. sureroller to. form a printing, couple, to which are: fed copy sheets. whoseupper surface is moistened with a solvent for the hectographic ink.

In one of such arrangements especially adapted for the printing of datafor production control systems, the rotatable drum carries two masterclips, one of which is a fixed clip extending substantially the full,length of the drum, whilst the second clip is a movable clip ex:-tending approximately half the length of the drum' and positioned behindthe fixed clip with respect to drum rotation, mechanism being providedfor traversing the movable clip to thefull extent. along the drum. Sucha machine is adapted to produce in one operation a copy of a fixedheading master and of one or more selected lines of an item mastersheet. For this purpose the heading master sheet is. placed in the fixedcli'p with the heading portion towards the. centre of the drum, and theitem master sheet is placed in the, movable clip and underneath theheading master. A masking; sheet is also, placed in the fixed clip insuch a position as to expose the one or more items of the movable mastersheet between the mask and the heading master. Copies are then taken ofthe heading together with the selected single item or items from themovable master sheet. Other items are selected by shifting the movablemaster clip along the drum. The normal spacing between the headingmaster and the mask is of one line of" the item master, and when it isdesired to print items of two-line width or more, it is necessary forthe operator to open. the fixed clip and to adjustthe position of themasking sheet to give the required spacing, In doing so care must betaken to avoid shifting the heading master, which, since it is carriedin the fixed clip, is also freed by opening the clip. Alternatively, asupplementary narrow mask must be used in conjunction with the existing.masking sheet, and for this purpose also operating skill is required toobtain correct adjustment. Whether or not an auxiliary mask is used,such operations of inserting and adjusting the additional mask or ofadjusting the mask in the fixed clip, add tothe number of manualoperations therefore increase the time printed copies. It is accordinglyone object of the present. invention to provide a clip arrangement; inamachine of the kind above referred to wherein rapid and accurateadjustment of the spacing or interval between the heading master and themask may'be effected. This object is achieved broadly by' providing,instead of a fixed clip taking up the full length of the drum,twousually fixed: at the width" to be performed and and expense ofproducing the the direction IV-IV' of Fig. 1.

2. clips, preferably alignedin the drum surface, one of wh ch s fix c pe tend n e a ni nt p tion of the drum length, for example onev half,whilst he e he is n. dli t b e nl wh h. ayh d. 5 le th is o he um un t ys eps c r e p nding. to the; minimumwidth of; any item which is to beprinted. fmm the ovab mas e According to the. present inventiontherefore, in a romy hecmg ap i dupl atin ma hi w l ps. a e p vid d i lm n par lel o he r m ax s 16. i; aid l psi s ed, and. he h r; o d, l psbein ash in ah e g h is o h r m in un a y st ps- Ac or i o neth r' spe tof he i ti i. a m s er: l p-- ar a gemen i a ta y hec a r i d is t nsmachine, comprises a fixed master clip extending for a par o he en th om ium movable m st r ip traversable lengthwise of the drum and lying;behind the fixed master clip. in the direction. of the rQla-tion of thedrum. during printing, I aligned. with respect. to. the length of thedrum with the said fixed master clip, the said adjustable master clipbeing. adjustable in theforward and. reverse directions n u i a y s ps-Further features. ofv the invention. relate. to a preferred form; ofspace shift mechanism. for an adjustable. clip whereby. the said. clipmay be shifted both in the forar and r v rse d re i y m n of a Pu h m4 ara k. an pawl. ech n m- S h p e r d orm of. hi mecha sm amp s a.

to, the. adjustable clip and. coeoperating v/ithv two pawl s.

one of which (the forward feed pawl) arrangedin. a the length of thepush. rod.

fixed position with respect to, andco-operates with. one rack, whilstthe. second pawl (herein referred to as the check pawl), is. secured to.a at n a e pe i o ith re p ct drum a coopera alternately w hhh e s Cl p7 opening means are also provided whereby the adjustable l p and. h fixel p ay e open d by a. c mmo ro e be i espec v e he a ju p s t on f eadjusta l cl p An x mple, of the mast l a ran emen a cord ng to the.inventio w l .now he e c b d in m e d t l with efe ence toh pan in d g Egure I s a s t on. taken thr gh t P ntin dru how-i a arra g men o clip pc ng me ha ism scc d ng. t0 t i vent en.

Figure 2 is. atten vie a a a ge calefi t 4mm from the direction of 11-11in Fig. 1 but omitting the rum n plat and h at n Figure 3 is anelevation of the drum and clips from the direction II I-III of Fig. 1'.

Figure 4 is a view' of the clip spacing mechanism from Figure 5 isanother view on a larger scale of part of the same clip spacingmechanism when the drum is rotated' 180 from the position in- Fig. 1

s Figure 5a is a detail of part of Figure 5.

Figures 6" and 7 are cross-sections taken as indicated through the clipspacing mechanism of Fig. 5.

Figure 8 is an end elevation of the right hand drum end plate with thedrum in adifferent position from Fig-- ure-l and showing further detailsof the clip spacing: mechanism and details of the clip openingmechanism..

Figure 9 is an elevation of a clip opening mechanism for one oi theclips shownv in Fig. 2.

Figure 10 is a detailed view of part of a latch mechanism shown in Fig.9.

carrying' a bearing boss 4 whereby the. drum may be and an. adjustablemaster clip.

u le. q hed a k fix to the length vef the.

journalled for rotation in the side frames of the machine (not shown).It will be understood that the drum cooperates with a counter-pressureroller which may be of known construction and that the details of thecounterpressure roller and the drum mounting form no part of thisinvention and will not therefore be described.

According to the invention which are indicated by the general references5 and 6 and which are aligned in a common radial plane (XX, Fig. 2), ofthe drum, the drum being shown with this plane vertical purely for ashowing of the parts in Fig. 1. Clip 5 is a fixed clip of about half thedrum length which remains at the right-hand side of the drum and isintended to carry a heading master which is not moved along the drum,and such clip will be referred to hereinafter as heading clip. Clip 6 isarranged at the lefthand end of the drum as viewed from the front of themachine and occupies rather less than half of the drum length to allowfor the required axial movement of the the drum carries two clips 19 ofthe ratchet plate as seen in Fig. 5, which rack clip by the clip spacingmechanism to be later described.

This clip, which will be referred to herein as the movable mask clip, isintended to carry a movable mask when the machine is operated for theselective printing of items from a movable master sheet.

The drum also carries a third clip, general reference indicated by the7, which is adapted to be moved the full length axially of the drum by afurther clip spacing mechanism to be referred to below. This clip, whichusually occupies about half the length of the drum, and is placed behindclips 5 and 6 in the direction of drum rotation, is intended to carry amaster sheet from which a selected item or items may be printed inconjunction with the heading when the respective clips are brought intotheir appropriate position, and may therefore be referred to as themovable item clip.

The drum is slotted along its length as shown in Figure 2 to provide agap of sufiicient dimensions to receive the clip assemblies eachcomprising the clips above referred to with the accessory parts formounting the clips in the drum.

The blade of the movable mask clip 6 is supported as shown in Figs. 2, 6and 7 between parallel back and front clip guide plates 8 and 8a, whichare secured together in any suitable manner. The front guide plate 8which is shaped to form a clip seat is rebated to receive therectangular lip 12 of the clip 6. The back is supported against abacking plate 9 which is rigidly fixed in the drum. The clip is held inthe closed position by retaining springs 13 anchored to plate 8a and isslidable radially between the plates 8 and 8a for opening by a mechanismto be described below. The clip 6 is also provided with an operatingmechanism now to be described for obtaining stepwise adjustment of theclip assembly, including the clip 6 and the guide plates 8 and 8a, awayfrom or towards the fixed master clip 5, these directions of adjustmentbeing referred to as forward and reverse. Forward feed motion ispositive but reverse motion is obtained by the tension of a spring 11.

A bracket 15 secured to the adjustable clip assembly by screws 16,carries a ratchet plate 17 provided on the opposite inside edges withtwo series of ratchet teeth 18 and 19, each having a pitch equal to thewidth of one .line of the printed matter from which copies are tobetaken, for example equal to /3 inch, and each of which series isstaggered with respect to the other by half the length of one tooth. Theattacking (straight) edges of all the teeth are directed to the sameside, in the present arrangement the right-hand side, whilst the slopingedges are on the left-hand side.

Two operating pawls 20 and 21, herein referred to as the forward feedand check pawls, are arranged to co-operate-with the said rack teeth.The forward feed pawl 20 is rotatably carried between two collars 22, 32

guide plate will be referred to as the feed rack. The spacing rod isurged into its right-hand (reverse) position by means of a compressionspring 28 mounted between a fixed collar 29 on the rod and one of thebearing brackets 26 above referred to. The motion of the rod in theright-hand (reverse) direction is limited by a collar 30 secured to therod at a suitable point. The forward motion of the rod is suitablylimited to a distance sulficient to advance the feed rack one tooth aswill be described below. The check pawl 21 is freely mounted on thespacing rod in a fixed position with respect to the drum and, for thispurpose, is held between two bushes .33 and 33a on the fixed bracket 24.The said check pawl 21 is likewise spring urged into contact with theabove mentioned feed rack of the ratchet plate. The

push rod is also provided with pawl releasing means, which may consistas shown in Figs. 6 and 7 of a plate 34 of a length suflicient to coverthe maximum spacing between the pawls. The plate 34 is suitably keyed tothe rod by means of lugs 37, and upon turning the rod clockwise througha small angle the plate 34 comes into contact with tail portions 35, 36of each pawl and so lifts the pawls clear of the rack for the purposelater referred to. A spring 38, which may serve for biassing the pawl 21on to the rack and partly for returning plate 34 and rod 23counter-clockwise, is anchored between the tail 35 of the check pawl andthe back plate 9.

v The above described arrangement allows the adjustable clip 6 to beracked forward one space at a time. Upon operating the spacing rod tothe left the forward feed pawl 20 engages one of the teeth of the feedrack 19 and moves the rack plate, and with it the clip, to the left onetooth space whilst the check pawl 21 is lifted by the motion of the rackand falls into the notch of the next adjacent tooth. The feed stroke ofthe rod is limited to one tooth by the distance between lug 37 and thefixed bush 33. By allowing the rod to return and repeating the stroke,the rack, and with it the adjustable clip, may be shifted in the forwarddirection by the required number of spaces according to the width ofany.

item required to be printed from the movable master sheet. Fig. 5 showsthe clip and rack fully spaced to the left. Fig. 1 shows the oppositeposition. It will be understood that the total spacing is limited onlyby relative lengths of the clips 5 and 6 and that the rack length couldbe chosen to suit this relation. However, it has been found that in theexample described a total spacing of two inches is sufiicient. Duringthis forward motion the check pawl locks the ratchet plate in each newposition and the opposite rack takes no part in the motion.

When it is desired to return the adjustable clip from the position shownin Fig. 5 to the position of Fig. 1, the spacing rod is rotated by asmall clockwise angle sulficient to lift both the feed pawl and thecheck pawl from their respective notches. Since the racks are staggeredby one half the length of each tooth, the check pawl, upon leaving anotch in the forward feed rack, enters an adjacent notch on the oppositerack, as shown in Fig. 5a, thus preventing the full return of theadjusta, small angle, the ratchet plate and withit the adjustable clip 6is moved under spring tension in the reverse direction by the length ofone tooth, i.e., the width of one line of the movable master and byrepeating this operat-ion the clip can be fully returned.

Mechanism will now be described whereby the clip spacing rod may bemanually operated from the operators position at the front of themachine.

Referring now more particularly to Figs. 1, 2 and 8, the latter of whichshows a view of the right-hand drum end plate from the direction II-IIof Fig. 1 after the drum has been rotated inthe anticlockwise directionthrough somewhat more than 90 from the position of Fig. 1 into the restposition in which the clips may be opened for inserting the mastersheets.

The right-hand end of the clip spacing rod, When in the normal position,rests against one arm 41 of a bell crank pivoted at 42 at the back ofthe drum end plate 3, and the lower arm 43 of the bell crank projectsthrough a hole 44 in the drum end plate and makes contact with the: noseof a lever 45 pivoted at 46 on the outside of the drum end plate.

The right-hand end of the clip spacing rod also carries a crank 48 keyedthereto which has a crank shaft 49 projecting through a hole 50 in thedrum end plate and engaging a slotted arm 51 of a bell crank pivoted at52 on the outside of the drum end plate.

A rock lever 53 is provided at 54 and the equal arms thereof each carrya roller 55. The above-mentioned bell crank arm 51 is biased by a spring56 to bring the second arm 57 of the bell crank against one of therollers 55 whilst the lever 45 is biased by a spring 58 to seat the heelof lever 45 against the second roller 55 of the rock lever 53, and stops59 and 60 are provided to stabilise the levers in the position showncorresponding to the normal rest position of the clip spacing rodretracted fully to the right of the drum.

A further lever 61 is pivoted at 62 in the right-hand side frame of themachine (not shown) and in such a position that when the drum is in themaster changing position shown in Fig. 3, a concentric operating surface63 of the lever 61 is symmetrically placed with respect to each of therollers 55 of the rock shaft 53. A manual operating lever 65 is pivotedin a convenient position at 66 in the right hand side frame (not shown)and is connected to the lever 61 by a linkage comprising the arm 67,link 68 and lever 69 which is slotted at 70 to receive the pin 64 oflever 61. The lever 65 is normally centred in the neutral position inFig. 8, by means of a centering device comprising arms 71 frictionallyconnected to lever 65 and embracing a fixed screw 74 secured in the sideframe and carrying operating pins 72 which are connected and drawntogether into contact with arm 67 by spring 73. Upon moving theoperators lever'65 from neutral in the feed direction the lever andlinkage operate to rotate lever 61 anti-clockwise and thereby to pushthe clip spacing rod forward through lever 45 and bell crank 41-.43.Upon moving the operators lever 65 in the reverse direction the leverand linkage operate to rotate lever 61 in the clockwise direction andthereby to oscillate the clip spacing rod through bell crank 515,7.

The fixed heading clip 5 is of similar construction to the movable maskclip 6 insofar as concerns the mounting of the clip between the clipguide plate 78 and the clip seat 79, and the details of this fixed clipmay follow known practice and will therefore not be further described.

It will be understood that a clip opening mechanism is provided foropening both the fixed clip 5 and the movable mask clip 6 when the drumis in the master changing position shown in Fig. 8. The main elements ofa clip opening mechanism for opening both clips 5 and 6 from one controlmember are shown in Figs. 1,. 2 and 8 of the drawing and comprise a cliplifting shaft whose axis is shown at 0 comprising a square rod 80extending through the length of the drum and journalled in bearings (notshown) in the end Plates 2 a d 3 l and pawl arrangement 6 thereof. Theclip lifting shaft carries two pairs of clip lifting arms indicated by81 and 82 respectively for open? ing the fixed clip 5 and the adjustableclip 6. For this purpose the clip guide plates 78 and 9 of the two clipshave pairs of slots at 83 and 84 respectively to receive the clip arms81 and 82 upon which are carried rollers 85 engaging upon the inner edgeof the clip blade. The clip lifting shaft carries at its right-hand enda clip lifting lever 86 which is operated through a rock shaft 87pivoted at 88 on the drum end plate. The rock shaft is adapted to beoperated by a lever mechanism (not shown) arranged in the side frame ofthe machine, when the drum is in the master changing position. Detailsof such a mechanism are not shown here but an example thereof isdescribed in our British patent application No. 4,240/54. Rotation ofthe rock shaft turns the lever 86 in the anti-clockwise direction andthereby causes the lifting arms to open both of the clipssimultaneously. Since the clip guide plate 9 remains stationary whilstthe clip 6 is adjusted along the drum, the arms and rollers 82 and areeffective to open the clip in any of its adjusted positions providedthat the inner edge 89 of the clip blade is parallel to the drum axisfor the required distance as shown in Fig. 5'. T It will be understoodalso that the movable item clip 7, which is carried within a guide plate91 and clip seat 92 in a similar manner to clips 5 and 6, must beprovided with clip opening means in order that the master sheet may beinserted therein when the drum is in the position shown in Fig. 8. Theclip opening mechanism provided for that purpose may be of anyconvenient type and oneexample of the kind in which the clip may" onlybe opened in its end position corresponding to that shown in Fig. 3 isshown in Fig. 9 of the drawings, wherein the clip blade is provided witha pair of inwardly projecting pins 93 which have their inner ends closeto a pair of sector-shaped operating levers 94 forming the side limbs ofa parallel linkage whose lower limb is a connecting link 95. Theconnecting link 95 lies opposite a nose 96 carried at the end of a shaft97 which is journalled and axially displaceable in the bearing boss 4 ofthe end plate. The shaft carries at its outer end a face cam (not shown)which is adapted to be operated by a lever in known manner to displacethe shaft axially to bring the nose 96 into contact with the link andthereby to operate the parallel linkage and to lift the clip by means ofthe pins.

To prevent axial movement of the clip during opening a latching deviceis provided as shown in Figs. 9 and 10 comprising a bell crank pivotedat 99 to the back plate 91 and having a long arm 102 adapted to hookover a pin 103 fixed to a bracket 104 on the drum end plate, and a shortarm 105 connected by a spring 106 to the link 95. The latch is normallyheld open by a stop 107' on link 95 and is closed during the initialidle movement of the link 95 before the levers 94 contact the liftingpins 93.

Mechanism is also provided for traversing the clip 7 along the drum.Such mechanism is preferably of the kind in which a clip operating rodpasses co-axially through one end of the drum end plate 3 and bearings4, and makes connection inside the drum to a lug 101 secured to the clipguide plate 91 and forming a sleeve bearing for the rod, whereby thedrum and clip may rotate round the rod whilst the rod is moving the clipaxially along the drum, during which movement the clip assembly isguided on a rod 98. The rod is connected outside the drum to a cliptraversing carriage (not shown) which is preferably of the kinddescribed in our British patent application No. 1 6,486/55 and comprisesa rack extending parallel to the .drum and externally thereof eitheroutside or between the side frames of the machine, control means beingprovided for obtaining step-by-step or full travel of h clip under theoperators control. The movable master is placed in the said movable itemclip 7, and the heading master is placed in the fixed heading clip 5. Amasking plate 90 (Figs. 2 and 3) is fitted to cover the drum gap toensure correct entry of the heading master in clip 5. A masking sheet isplaced in the movable mask clip 6, which, as described above, is axiallyaligned with the fixed clip. The clip 6 is normally spaced from thefixed clip by the width of one item of the movable master, this Widthbeing shown at d in Fig. 1, so that in the normal operating position thewhole of the fixed master and one item of the movable master are exposedfor printing. By operating the clip spacing rod as above described thewidth of the movable master exposed for printing can be adjusted to 2,3, 4 or any convenient number of spaces up to the maximum provided bythe rack and pawl. Hence the printing of items of variable width fromthe fixed master and of a heading from the heading master may beeffected without carrying out manual masking adjustment or mask changingoperations which have formerly been necessary in machines of this type.

. We claim:

1. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotatable printing drum, a first axiallymovable clip for securing an item master sheet to said drum, said clipbeing located in a drum slot extending axially of said drum and beingadjustable over substantially the full axial length of said drum, firststep-by-step shift means for moving said master clip within said drumslot in unit steps of predetermined length, a fixed position master clipdisposed axially of said drum at a position angularly spaced forwardlyfrom said first axial movable clip in the direction of drum rotation,said fixed position clip being located at one end of said drum and beingof lesser axial length than said drum, a second axially movable clip forsecuring a masking sheet, said second axially movable clip being locatedin a drum slot extending axially of the drum at a position justangularly spaced forwardly from said first axially movable clip in thedirection of drum rotation, said second axially movable clip beingadjustable over a range of movement embracing that part of the drumlength which is not embraced by said fixed position clip and secondstep-bystep shift means for shifting said second axially movable cliplengthwise of the drum in unit steps of predetermined length in eitheraxial direction.

2. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotatable printing drum, a first axiallymovable clip for securing an item master sheet on said drum, said clipbeing movable in a drum slot extending axially of the drum forsubstantially the full axial length of said drum, first step-by-stepshift means for shifting said master clip within said drum slot in unitsteps of predetermined length, a fixed position master clip extendingaxially of the drum and substantially parallel to said first axiallymovable clip but spaced angularly from said first movable clip in thedirection of drum rotation, said fixed position clip being of restrictedlength less than the length of said drum and being positioned at one endof said drum, a second axially movable clip for securing a masking sheeton said drum, means defining a second axial drum slot in said drum incontinuation of said fixed clip over that part of the drum length notoccupied by said fixed clip, said second axially movable clip beinglocated in said second drum slot and second step-by-step shift means formoving said second axially movable clip in either direction in saidsecond drum slot in unit steps of predetermined length.

3. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotatable printing drum, a first axiallymovable clip for securing an item master sheet to said drum said'clipbeing located in a drum slot extending substantially the full axiallength of said drum, first step-by-step shift means for shifting saidfirst movable clip lengthwise of said drum, a fixed position master clipparallel with and angularly spaced forwardly from said first movableclip in the direction of drum rotation, a second axially movable clipfor securing a masking sheet, said second movable clip being located ina drumslot parallel with and angularly spaced forwardly from said firstmovable clip in the direction of drum rotation, and second step-by-stepshift means for adjusting said second movable clip in either axialdirection in unit steps of predetermined length, said second shift meansincluding a ratchet toothed plate secured to said second movable clip, amanually operable reciprocable and rotatable spacing rod extendingparallel to the drum axis for moving said second movable clip axially ina first direction, a check pawl whose position is fixed relative to saiddrum, said pawl co-operating with said ratchet plate teeth and meansoperatively connected to said spacing rod for lifting said check pawlfrom said ratchet teeth by rotation of the rod about its axis for movingsaid second movable clip in a second direction opposite to said firstdirection.

4. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotatable printing drum, a first axiallymovable clip for securing an item master sheet to said drum, said firstmovable clip being located in a drum slot extending substantially thefull axial length of said drum, first stepby-step shift means forshifting said first movable clip lengthwise of said drum in unit stepsof predetermined length, a fixed position master clip parallel with andangularly spaced forwardly from said first movable clip in the directionof drum rotation, a second axially movable clip for securing a maskingsheet, said second movable clip being located in said drum slot parallelwith and angularly spaced forwardly from said first movable clip in thedirection of drum rotation, and second stepby-step shift means foradjusting said second movable clip in either axial direction in unitsteps of predetermined length, said second step-by-step shift meanscomprising a toothed ratchet plate secured to said second movable clip,a manually reciprocable and rotatable spacing rod extending parallel tothe drum axis within said drum and a pair of pawls operable respectivelyby reciprocation and rotary movement of said spacing rod, said pawlseach being mounted for movement in planes transverse to the spacing rodaxis for engagement with and disengagement from the teeth of saidratchet plate.

5. A rotary hectographic copying machine according to claim 4, whereinsaid ratchet plate has two opposed series of rack teeth of equal pitch,one series being staggered with respect to the other, said two series ofteeth being arranged respectively on opposite edges of an aperture insaid ratchet plate, wherein a first one of said pair of pawls isconstituted by a feed pawl carried by said spacing rod and wherein thesecond one of said pair of pawls is constituted by a check pawl mountedin a fixed position with respect to the drum, said two pawls eachengaging with only a first one of said series of rack teeth duringforward feed of said second movable clip by reciprocatory movement ofsaid spacing rod and said check pawl being engaged alternately with atooth on said first series of rack teeth and with the next adjacenttooth on the other of said series of rack teeth by oscillatory rotarymovement of said spacing rod during the reverse feed of said secondmovable clip.

6. A rotary hectographic copying machine according to claim 5, whichincludes spring means for normally spring biasing each of said pawlsinto engagement withsaid first series of ratchet teeth and whichincludes lifting means for simultaneously lifting each of said pawlsfrom said first series of ratchet teeth by rotation of said spacing rod.

7. A rotary hectographic copying machine according to claim 4 includingclip opening means for said fixed position clip and said second movableclip, said opening means having a common manual control member wherebythe two clips may be opened simultaneously irrespective of the axiallyadjusted position of second movable clip.

8. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotatable printing drum, a first axiallymovable clip on said drum for securing an item master sheet therein,first shift means for shifting said first axially movable cliplengthwise of the drum, a fixed position clip on said drum for securinga heading master therein, said fixed position clip being parallel withbut angularly spaced forwardly from said first movable clip in thedirection of drum rotation and extending from one end of said drum fornot more than half the axial length of the drum, a second axiallymovable clip on said drum for securing a masking sheet therein, saidsecond movable clip being disposed in axial alignment with said fixedposition clip, and second shift means for adjusting the axial positionof said second movable clip, said second shift means comprising a clipspacing rod mounted within said drum and a ratchet and pawl couplingbetween said spacing rod and said second movable clip.

9. In a rotary hectographic copying machine of the kind employing mastersheets removably secured to a rotary printing drum, a first axiallymovable clip for securing an item master sheet on said drum, first shiftmeans for shifting said first movable clip lengthwise of said drum, afixed position clip on said drum for securing a heading master therein,said fixed position clip being parallel with but angularly spacedforwardly from said first movable clip in the direction of drum rotationand extending from one end of said drum for not more than half the axiallength of said drum, a second axially movable clip on said drum forsecuring a masking sheet therein, said second movable clip beingdisposed in axial alignment with said fixed position clip, and commonclip opening means for said fixed position clip and said second movableclip operable by a common manual control member.

10. In a rotary hectographic copying machine of the kind employingmaster sheets removably secured to a rotatable printing drum, a firstaxially movable clip for securing an item master sheet to said drum,said clip having a length substantially equal to half the length of thedrum and being movable in a drum slot extending substantially the fullaxial length of said drum, first shift means for shifting said masterclip lengthwise of the drum, a fixed position clip on said drum forsecuring a heading master therein, said fixed clip being parallel withbut angnlarly spaced forwardly from said first movable clip in thedirection of drum rotation and extending from one end of the drum forsubstantially half the length of the drum, a second axially movable clipaxially aligned with said fixed position clip and of shorter length andstep-by-step shift for moving said second movable clip axially in eitherdirection with respect to said fixed position clip in unit steps ofpredetermined length.

11. A rotary hectographic copying machine as claimed in claim 10 inwhich said step-by-step shift means comprises a manually reciprocableand rotatable spacing rod extending parallel to the drum axis withinsaid drum, and a ratchet and pawl coupling between said spacing rod andsaid second movable clip, said coupling including a feed pawl movablelongitudinally of the drum by said spacing rod and mounted for movementin a plane at right-angles to said rod axis by rotary motion of saidrod.

12. A rotary hectographic copying machine as claimed in claim 11 whichincludes spring means for urging said second movable clip in thedirection opposite to that by which it is movable by said feed pawl andin which said step-by-step shift means includes an escapement mechanismoperable by oscillatory rotary motion of said spacing rod forcontrolling movement of said second movable clip by said spring means.

13. A rotary hectographic copying machine as claimed in claim 12 whichincludes a first lever mechanism mounted on said drum for impartingreciprocatory motion to said spacing rod, a second lever mechanismmounted on said drum for imparting rotary motion to said spacing rod,each of said lever mechanisms including operating elements projecting atone end of said drum, a stationary framework for the machine, a manualcontrol member mounted on said framework and movable in either of twodifferent directions from an intermediate rest position and a rockingmember mounted on said framework at a position adjacent said operatingelements when said drum is in a predetermined rest position, saidrocking member being arranged to engage and operate said first levermechanism when said manual control member is moved in one direction andto engage and operate said second lever mechanism when said manualcontrol member is moved in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS2,237,363 Ritzerfeld Apr. 8, 1941 2,440,635 Little et al. Apr. 27, 19482,604,847 Kvarnegard July 29, 1952 2,707,433 Roberts May 3, 1955 FOREIGNPATENTS 562,502 Great Britain July 5, 1944 113,374 Sweden Mar. 6, 1945

